The present invention relates to a passenger side airbag, which is filled with gas during an emergency situation such as, for example, a frontal or side impact. It will be appreciated that the structural benefits and design principles may of course be extended to airbags typically employed in other areas of the vehicle, such as a side airbag, for example.
Current airbag cushion designs may include multiple chambers and may incorporate an inter-chamber valving system that allows gas to flow from one chamber to another. These cushions are configured to rapidly contact a vehicle occupant when inflated, to limit movement of the passenger head, neck and thoracic regions. However, these cushion designs do not differentiate between these different regions with regard to the stiffness or resistance of the various portions of the airbag to contact with each region.
Research has shown that the masses of the various body portions contacting an airbag differ greatly. For example, the mass ratio of the Thorax to Head & Neck regions may range from between 5:1 to 8:1, depending on the sex of the individual. Due to the differences in body part masses and the dynamics of contact between the occupant and the cushion, it has proven difficult to design a multi-chamber airbag which provides optimum protection for each portion of the body contacting the airbag.
Thus, a need exists for an airbag design which permits the stiffness or resistance to occupant impact provided by each portion of the airbag to be adjusted according to the time elapsed since the initiation of airbag deployment, the size of the occupant, and/or the masses of different portions of the occupant's body contacting an associated portion of the airbag. A need also exists for an airbag structure adaptable for controlling a neck extension moment (defined as an undesirable rotation of the head and neck about the torso at the neck-torso junction) resulting from contact of the passenger with the airbag.